System for governing railway traffic



W- K. HOWE.

SYSTEM FOR GOVERNING RAILWAY TRAFFIC.

APPLICATION FILED NOV. 16. 1915. 7

1,354,254. PaltentedSept. 28,1920.

2 SHEETS-SHEET I.

INVENTOR ATTORNEY W. K. HOWE.

SYSTEM FOR GOVERNING 'RAILWAY TRAFFIC.

APPLICATION FILED NOV-16, 1915.

m M 2. y H M T 9E R/L n 8 m/ m m M m M E am m 2 E. t n w m P one trackrail 1 of the track is UNITED STATES PATENT OFFICE.

WINTHROP K. HOWE, OF ROCHESTER, YORK, 'AS SIGNOR T0 GENERAL RAILWAYSIGNAL COMPANY, OF GATES, NEW YORK, A CORPORATION OF NEW YORK.

SYSTEM FOR GOVERNING RAILWAY TRAFFIC.

Specification of Letters Patent.

Patented Sept. 28, 1920.

Application filed November 16, 1915. Serial No. 61,789.

To all whom 2'25 may concern:

Be it known that I, WINTHRoP K. HOWE, a citizen of. the United States,and a resident of the city of Rochester, in the county of onroe andState of New York, have in vented a new and useful System for GoverningRailway Trafiic, of which the follow ing is a specification.

This invention relates to systems for governing railway traffic, andmore particularly to electrically operated devices and controllingcircuits therefor constituting a combined signaling and automatic traincontrol system.

One of the objects of this invention is to devise a suitable system ofthe character specified which will accordance with traffic conditions,and which will govern the electrical condition of appropriate contactrails or ramps by means of which the train will be automaticaly governedin case these signals are disregarded.

Other objects and advantages will appear as the description of theinvention progresses and the novel features of the invention will beparticularly pointed out in the appended claims.

In describing the invention in detail, reference is had to theaccompanying drawing, wherein I have illustrated a preferred phys icalembodiment of my invention, and wherein like characters of referencedesignate corresponding parts throughout the several views, and inwhich:

Figures 1 and 2 are diagrammatic views of a portion of a track,signalsfor governcuits, which embody this invention. These. 'two figuresshow adjacent portionsv of the track and are intended to be placedtogether end to end with Fig. 2 at the right.

Referring to the accompanying drawing, electrically continuous, theseparate rails thereof being bonded together, and the other trackrail 2is dividedby ins'ulating joints 3 into a series of track sections A, B,C, D and E. At the entrance to the track sections B, C, D and E,hereinafter-termedblocks, is a suitable signal for governing traffic inthe direction indicated by the arrow X, said signals being give propersignals in designated S, S S and S These signals may be of any suitableconstruction, but are shown as so-called light signals, which eX- hibitdifferent colored lights, such as red, yellow and green, as theirindications. Located adjacent to each of said si nals is an insulatedramp, designated P, P, 2 and P These ramps are intended to cooperatewith suitable contact shoes carried by the train and in some appropriatemanner communicate the information concerning the traffic conditions tothe train. The contact shoe and automatic train control apparatus may beof any suitable construction, it being merely essential for theoperation of this system that the automatic train control apparatus beresponsive to different potential differences between the ramps and thetrack rails, and in the particular arrangement of controlling circuitsshown, it is assumed that an automatic .train control system ofappropriate construction is used so that, when the train encounters aramp between which and the track rail a high differenceof potentialexists, the automatic train control apparatus will be restored to itsnormal or idle condition; that a medium difference of potential willcause the train control apparatus to be held in the position which itthen occupies; that a low diiference of potential causes the automatictrain control apparatus, so far as the controlzof the speed of the trainis concerned, to be set into operation; and that no difference ofpotential causes the full braking force to be immediately applied. It isto be understood, however, that this selection of voltages is notcompulsory and that with other typesof train control apparatus othervoltages may be used.

Extending along the track are two wires 4 and 5, which are connected toa suitable -source of alternating current, asa generator 6, and whichserve to supply the power for operating the signals and relays andenergizingthe ramps. Since the controlling devices and controllingcircuits associated with each of the signals S and the ramps P .are,with minor exceptions, the same, the

ing of the nature and tion to describe these relays further than to' theexit end, the secondary of a transformer 7 is connected by wires 8 and 9to the track rails 1 and 2. Associated with each signal S aretransformers 10 i and 11, the first serving to supply power for lightingthe red,

green and yellow lights of said signal, the,

ondary having three taps, 16, 17 and 18 representing high, medium andlow voltages,

respectively. A

To the end of each block, opposite to the end to which the transformer 7supplies current, is connected a track relay T. These track relays T areshown according to established convention of the type comprising twoseparate coils or windings 20 and 21, the coil 20 being connected acrossthe track rails 1 and 2, and the coil 21 benig connected at one terminalby conductors 22, 23, 24, and 25 to the middle tap 13 of the secondaryof the transformer 11 and at the other terminal by conductors 28, 27 and26 to one terminal tap 14 of the secondary of the transformer 11, markedpositive. In order to energize the track relay T and cause its armatures29, 30, 31, 32 and 33 to be raised it is necessary to supply current toboth of its windings 20 and 21, and since one of said windings 21ispermanently connected toa source of current, the energization ordeenergization of the other windings 20 determines whether or not itsarmatures are raised or lowered.

Also associated with each signal S is a relay H, hereinafter termed thehome relay, and a relay G hereinafter termed the distant relay, it beingunderstood that these terms are chosen merely for the sakeof convenienceand do not suggest any particular con- I struction orv functlon of therelays so des-- ignated. These relays H and G are shown of the typecommonly known as three-position alternating current relays, andcomprise two separate coils or windings. The construction andcharacteristics of this type of relay is well known in the art, audit isa clear understanddeemed unnecessary for scope of this invensay that itis necessary to have both of the separate windings of these relaysenergized in order to operate their armatures, and that the relativepolarity at any given instant of the terminals of said windingsdetermines the direction in which said armatures areoperated. Theseparate windings of the relay H are designated 34 and 39,. and thewinding 34 is permanently connectedby conductors 35, 24 and 25, and byconductors 88, 37 and 36 to the negative and .neutral taps 12 and 13,respectively, of the secondary of the transformer 11, so that saidwinding 34 is energized at all times The controlling circuits for theother winding 39 of the relay H will be set forth fully hereinafter inthe description of the operation. The armatures 40, 41, 42, 43 and'44 ofthe relay H are represented according to established convention and mayoccupy a position, shown in full lines in the drawing, to the left, thisposition for the relay H being hereinafter termed the normal position; amiddle position, corresponding to the deenergization of the winding 39and hereinafter termed the neutral position; and a position to the rightof the position shown in the drawing, this position being hereinaftertermed the reverse position.

The separate windings of the distant 'relay G are designated 46 and 47,the winding 47 being permanently connected by con ductors 53, 54, 55,23, 24 and 25, and by conductors 59, 58, 57, 56, 37 and 36 to theneutral and negative taps 13 and 12, respectively, of the secondary ofthe transformer 11, so that said winding 47 is energized at all times. iThe armatures 48, 49, 50, 51, 52 of the distant relay G have threedifferent positions indicated and designated the same as the threedifferent positions above mentioned of the home relay H.

Also associated with each signal S is a relay 60, hereinafter designatedthe stick relay, having two armatures 61 and 62, which are connected byand arranged to be operated by a push button 63 or other suitablemanually operable device. The circuits controlled by the armatures 61and 62 of the stick relay 60 will be pointed out fully hereinafter.

Extending the full length of the track is a common wire 100, which isconnected by a conductor 99 to the neutral tap 13 of the secondary ofeach of the transformers 11, and for convenience and'clearness some ofthe operating circuits set forth hereinafter Will be traced from thecommon wire 100 at one point back to the common wire 100 at anotherpoint, it being obvious that the commonwire serves to complete thecircuits thus traced.

Operation-The operation of the signals S will be consideredfirst, and itwill be assumed that a train commences at the block A, and as it passesalong the track, the difdifferent circuits and different signals set upbehind it will be traced. at length. When the train enters the block Bits wheels and axles shunt the winding 20" of the track relay T andcause the armatures 'of said track relay to drop. The dropping of thearmatures 30 and 31 of the'track relay T causes a reversal of thearmatures of the home relay H by reason of the fact that the polarity ofthe winding 39 of said home tors 25, 24, 23, 55 and relay is changed. Toillustrate, the circuit for normally energizing the winding 39,-

when the track relay T is energized, is as follows:

CIRCUIT NUMBER ONE.

CIRCUIT MBER TWO.

Commencing at the neutral tap 13, thence as in circuit number one to thearmature 30 of the track relay T, thence by conductor 71 to the armature31 of the track relay T in its lower position, and conductors 72, 57,56, 37 and 36 to the negative tap 12.

When the armatures of the home relay H are reversed, the armature 40closes a stick circuit for the winding 39 of said relay as follows:

- CIRCUIT NUMBER THREE.

Commencing at the neutral tap 13, conduc- 64, winding 39, conductors 65and 73, armature 40 reversed, conductor 74, armature 32 of the trackrelay T in its lower position, and conductors 75, 56, 37 and Y36 to thenegative tap 12.

By reason of this stick circuit number three the armatures of the homerelay H will be held in their reversed position so long as the trackrelay T is denergized, that is, so long as any portion of the trainoccupies the block, B. To understand the controlling eifect'produced onthe signal S by the reversal of the armatures of the home relay H, itseems desirable to trace the circuit for the green lamp G, which isn0rmally closed, said circuit being as follows:

CIRCUIT NUMBER FOUR.

When the armature 44 of the home relay H is reversed it interrupts thecircuit for the green lamp number four hereinbefore traced, and closes acircuit for the red lamp as follows:

CIRCUIT NUMBER FIvE. Secondary of the transformer 10, conductor 76,armature 44 reversed, conductor 83, red lamp R and conductors 84 and 82back to the secondary of the transformer 10.

From the foregoing it can be seen that when the train enters the block Bthe green lamp in the signal S is extinguished and the red lamp lighted,thereby changing the aspect ofthe signal S from proceed to stop.

As the train proceeds and enters the block C it causes thedeinergization of the track relay T and the dropping of the armatures 30and 31 of the track relay T causes a reversal of the armatures of thehome relay H in the same way as hereinbefore described in connectionwith the home relay H, and thereby causes a redlight to be displayed atthe signal S Likewise the stick circuit for the home relay H analogousto circuit number three for the home relay H, is set up, so that thisred light is maintained so long as any portion of the train remains inthe block C.

The armature 29 of the track relay T interrupts a circuit for normallyenergizing the winding 46 of the distant relay C, said circuit being asfollows:

CIRCUIT NUMBER SIX.

Commencing at the common wire 100, conductors 99, 24, 23, 55, 54 and 85,winding 46, conductor 86, armature 29 of the track relay T in its upperposition, conductors 87 and 88 armature 42 of the home relay H normal,conductors 89 and 26 positive tap 14 secondary of the transformer 11neutral tap 13 and conductors 25 and 99 'back to the common wire 100.

i The denergization of the winding 46 of -the distant relay G causes thearmatures of said relay to assume their neutral position,- and thearmature 49 of said distant relay (i interrupts the circuit number twowhich at that time is holding the armatures of the home relay Hreversed, whereupon said an matures of said home relay H move to theirneutral position, providing the train has en tirely left the block B.The dropping of the armature 40 to its neutral position breaks thecircuit number three, but the armature 44 in its neutral position doesnot interrupt the circuit number five'for the red lamp R, since thecontact coiiperating with the arma ture 44 is constructed so as to makecontact with said armature in both its reversed position' and itsneutral position.

From the foregoing it can be seen when the train has entirely passedfrom the block B into the block C a red light is displayed at the signalS and also at the signal S As the train proceeds and enters the block Dit causes a denergization of the track relay T and the dropping of itsarmatures.

-The armatures 30 r and 31 cause a reversal of the armatures of the homerelay H in the same way ashereinbefore described, and I the armature 32establishes the stick circuit, analogous to the circuit number three,for the home relay H The reversal of the armatures of the home relay Hextinguishes the green lamp Grand lights the red lamp R at the signal Sin the same way as before explained. The armature 29 of the track relayT interrupts a circuit analogous to circuit number six, for the distantrelay G and causes its armatures to assume their neutral position, withthe same effects as hereinbefore described in connection with thedistant relay G, principally the moving of the armatures of the homerelay H to their neutral positions. \Vhen the armature 41 of the homerelay H moves to its neutral position and the train has entirely leftthe block C, so that the track relay T is energized, a circuit forenergizing the winding 46 of the distant relay G of apolarity oppositeto its normal polarity, is established as follows:

CIRCUIT NUMBER SEVEN Commencing at the common wire 100, conductors 99,24, 23, 55, 54 and 85, winding 46 of the distant relay G, conductor86,armature 29 of the track relay T conductors 87 and 90 armature 41 in itsneutral position, conductors 91 and 86 negative tap 12 of the secondaryof the transformer 11 neutral tap 13 and conductors 25 and 99 back tothe common wire 100.

It can be seen that the last traced circuit is of different polaritythan the circuit number six for normally energizing the winding 46 ofthe distant relay G, and, consequently, the armatures of said distantrelay G are reversed. The armature 49 in its reversed position contactswith conductor 94, which is connected to conductor 66, and since thetrack relay T is energized, the normal circuit number one for ener izingthe winding 39 of the home relay lished, and the armatures of said homerelay H are moved to their normal position, as shown in the drawing. Thearmature 44 of the home relay H interrupts-the circuit number five forthe red lamp R; and, remembering that the armature 48 of the distantrelay G is in its reversed position, a circuit for lighting the yellowlamp Y is established as follows:

CIRCUIT NUMBER EIGHT.

Secondary of the transformer 10, conductor 76, armature 44 normal,conductor 77, armature 48 reversed, conductor 92, yelloinlamp 18estabcaution signal and two danger or stop signals, this arrangementbeing known in the art as aone block overlap.

Next, assume that the train proceeds into lay H and since the block C isnot occupied and the armature 30 of the track relay T is in its upperposition, this circuit is completed and causes the armatures of the homerelay H to assume their normal position, as shown in the drawing. Themovement of the armature 41 of the home relay H to its normal positionbreaks the circuit number seven for energizing the winding 46 of thedistant relay G with current of a polarity opposite to its normalpolarity, and closes the circuit number six for energizing said winding46 with ourmatures of the distant relay G are restore to their normalposition, thereby breaking the circuit number eight for the yellow lampY of the signal S and closin circuit number four for the green lamp ofthe signal S. e

From the foregoing description, taken in rent of the normal polarity, sothat the arconnection with the circuits illustrated in the drawing, theoperation of the signals will be apparent to one skilled in the art ofrailway signaling; but it is also contemplated according to thisinvention to provide ramps suitable for governing an automatic traincontrol system so as to enforce obedience to these signals, and thisinvention further contemplates in controlling the electrical conditionof these ramps by means of the1 same relays used for controlling thesigna s.

To enable a clear understandin of the controlling circuits for the rampsit will be assumed that a train occupies the block D, having passedthrough the blocks A, B and C and having placed the armatures of thedifferent home and distant relays in position to display two stopsignals and a caution signal behind it. At the si al S the armatures ofthe home relay 2 at this time are reversed and the armatures of thedistant relay G are normal. At the signal S, the armatures of both thehome relay H and the distant relay G are neutral. At the signal S, thearmatures of the home relay 'H are normal and the armatures of thedistant relay G are reversed. Assume that a following train is in theblock A and is about to enter the block B. Before the first pair ofwheels and axle of this following train enter the block B, the contactshoe, carried by that train engages the ramp P. At this time a highdifference of potential exists between the ramp Pand the track rail 1according to the following circuit.

, CIRCUIT NUMBER NINE.

Commencing at the ramp P, conductor 101, armature 33 of the track relayT in its upper position, conductor 102, high voltage tap 16 of the,transformer 15 and conductor 19 to the track rail 1.

When the first pair of wheels and axle of the following train enter theblock B the track relay T is shunted and its armature 33 drops, therebyinterrupting the circuit number nine; and, remembering the positions ofthe a-rmatures of the home and distant relays and G, a circuit forcreating a low difference of potential between the ramp P and the trackrail 1 is established as follows:

CIRCUIT NUMBER TEN.

Commencing at the ramp P, conductor 101, armature 33 of the trackrelay-T in its lower position, conductors 103 and 104, armature 51 ofthe distant relay G reversed, conductors 105 and 106, low voltage tap 18of the transformer 15 and. conductor 19 to the track rail 1.

This low difference of potential between the ramp P and the track rail1, in accordance with the characteristics of the automatic train controlsystem which is assumed to be used with the trackway circuits shown andhereinbefore described, causes the speed of the following train to becontrolled in any appropriate way,so as to be brought to a stop, or to asafelow speed, by the time it reaches the end of the block B. The signalS indicates stop, but gineer of the train for some reason fails to bringthe train to a stop and said train enters into the block C. At thistime, the track relay T being denergized and its. armature 33 in itslower position, there will exist no difference of potential between theramp P and the track rail 1, since the armature 51 of the distant relayG is in its neutral position, and interrupts the circuit analogous tothe circuit number ten, and since the armature 43 of the home relay H isin its neutral position. Consequently, in accordance with thecharacteristics of the automatic train control system, the emergencybrakes will be immediately applied when the following train attempts toenter the block C contrary to the stop indication of the signal S Tobring out one further feature of the controlling circuits shown andhereinbefore described, it is assumed that a train is in the block A andabout to enter the block 13, and

assume that the en CIRCUIT 'NUMBER ELEVEN.

Commencing at the ramp P, conductor 101, armature 33 of the track relayT in its lower position, conductors 103 and 107, armature 52, normal,conductor 108, medium tap 17 of the transformer 15 and conductor 19 tothe track rail 1.

Incidentally, it may be noted that a circuit analogous to this circuitnumber eleven -1s establlshed when a train passes from the block G intothe block D, while another train occupies the block D; but thiscondition is hypothetical, since the following train could not pass thedanger signal at the signal S without being automatically stopped, and

hence could not get as far as the signal S while the block D wasoccupied.

According to the characteristics of the automatic train control systemwhich is assulned to be used with the particular arrangement of circuitsshown and described,

this medium voltage holds the parts of said train control system in thepositions that they then occupy.

It sometimes happens that two or more motor cars or locomotives, eachequipped with the automatic train control apparatus,

.are included in the same train; and it is preferable to connect thetrain control apparatus on these different cars or locomotives by acontinuous conductor or bus so that theapparatus on these different carswill be restored simultaneously to their normal positions. It may alsohappen that such a train will be longer than a block, and that while thecontact shoe of one locomotive is in contact with one ramp, the contactshoe of another locomotive is in contact with another ramp in the rear.There is a serious difficulty which arises under such conditions, anditis the purpose of the circuit shown and described to remedy thisdifliculty.

nals S and S being at danger and the signal S at caution for the reasonshereinbefore set forth; and assume that another train, which is longerthan the block B, approaches the signal S and for some reason fails toobserve this signal and enters the block C.

' this position when the following train en- I run over the trackway. Toexplain how this tered the block B, and since they are held in thereverse positionby the stick circuit number three. With the armatures ofthe home relay H and the distant relay G in the positions justdescribed,a low difference of potential exists between the ramp P andthe track rail 1 according to a, circuit as follows: Commencing at theramp P, conductor 101, armature 33 of the track relay T in its lowerposition, conductors 103 and 107, armature 52 of the distant relayGneutral, conductor 122, armature 43 of the home relay H reverse,conductors 123 and 106, low voltage tap 18 of the-transformer 15 andconductor 19 to the track rail 1. This low difference of potential issuflicient to energize the bus and prevent the emergency application ofthe brakes.

The wiring connections associated with the block C between the signals Sand S illustrate those which are used when a block is shorter than thelength of trains such as arrangement of circuits prevents a ramp, as

P being energized when a train, attempts,

to enter a block, as the block'D, With the next block ahead, as E,occupied, assume a train passes into blocks B and'C and for some reasonenters block D, this train being long enough so that its rear end isopposite ramp P Under these conditions, the armatures of the distant'relay and that the armatures of the home relay H are reversed; Underthese conditions the partial circuit for the ramp P is as follows:Commencing at the ramp P conductor 101 armatu 33 of the track relay Tconductors 103 and 107 armature 52 of the distant relay Gr neutral,conductor 109 armature 43 0f the home relay H reverse, conductor 110conductors 111 or 1.12 armature 45 of the home relay H normal orreversed, conductors 113 and 106 low voltage tap 18 of the transformer15 and conductor 19 to the track rail 1.

From this last traced circuit it can beseen that the low difference ofpotential between the ramp P and the track ,rail 1 is controlled by thehome relay H as well as by the home relay H and the distant relay G andunder the particular conditions as- G are neutral train, wishing to passbutton 63 and raises the armatures sumed, that is, with a train in theblock E and where the emergency application of the brakes should begiven when the following train attempts to enter the block D, the lastabove traced circuit is interrupted at the armature 45 of the home relayH since the armatures of this home relay H are in their neutralpositions. This latter state ment may not be obvious, and to explain,reference is made to circuits numbers one, two, three and six. Fromanalogy to these circuits it can be seen that the armatures of the homerelay H were reversed when the train now assumed to be ahead in theblock E passed the signal S by breaking circuit number one andestablishing circuit number two, that when the armatures of said homerelay H were reversed they were held in their reverse position by thestick circuit number three, and that as soon as the train left the block"'D, said stick circuitwvas interrupted and the' home relay H placedunder the control of the distant relay G In this way, low difference ofpotential is cut off from the ramp P so that this low difference ofpotential cannot interfere with the proper emergency application of thebrakes, in case a train attempts toenter the block D while the block Eis occupied by another train.

It may happen that an engineer will wish, for some reason, to pass adanger signal Without having the automatic train control apparatus setinto operation, as. for instance, because of the failureof thesignal;and for this purpose the push button 63, the relay 60 and itsarmatures 61 and 62 are provided. Assume that a train occupies thebloclg C and that another train is in the block A about to enter theblock B. Then; for the reasons hereinbefore explained, the red lamp Ratthe signal S will be displayed, and as soon as the train enters theblock 13 no difference of potential willexist between the ramp P and thetrack rail 1. Also, the armatures of both the home and distant relays Hand G are in their neutral positions; The engineer or motorman of thefollowing the signal S, presses the push 61 and 62 to their upperposition. The armature 62 in its upper. position establishes a circuitfor ener izing the winding'39 of the home relay tures of said home relayto be moved to their reverse position, said circuit being as followsCIRCUIT NUMBER TWELVE.

position, conductors 116 and 117, armature 50 of the distant relay Gneutral, conductors which causes the arma-' to the negative tap CIRCUITNUMBER THIRTEEN.

Commencing at the ramp P, conductor 101, armature 33 of the track relayT in its lower position, conductors 103 and 107, armature 52 of thedistant relay G neutral, conductor 122, armature 43 of the home relay Hreverse, conductors 123 and 106, low voltage tap 18 of the transformer15 and conductor 19 to the track rail 1.

It should be noted that this last traced circuit number thirteen is notestablished until the track relay T is denergized; and also that thereversal of the armature 40 of the home relay H, which ordinarily wouldestablish the stick circuit number three, does not establish this stickcircuit until the track relay T is denergized. The train, however, isstill in the block A and can only enter the block B, without beingautomati- 'cally stopped, while the armatures of the home relay H arereversed. It is contemplated that the re-set button 63 will be disposedat some convenient point along the trackway in such position that themotorman or engineer may gain access to it by breaking a seal oroperating a lock without leaving the cab; and with this location of there-set button it is necessary to hold the re-set button raised, after ithas once been raised, while the train proceeds and enters the block B,whereupon the dropping of the armature 32 of the track relay Tcloses thestick circuit number three. This holding of the re-set button 63 isaccomplished by the stick relay 60 and the armature 61; and when thearmature 61 is raised, the relay 60 is energized and holds both thearmatures 61 and the armatures 62 in their upper positions, theenergizing circuit for the stick relay circuit being as follows:

CIRCUIT NUMBER FOURTEEN.

Commencing at the positive tap 14 of the transformer 11, conductors 26,27 and 70, armature 30 of the track relay T in its upper position,conductors 69 and 121, relay 60, conductor 120, armature .61, conductors119 and 117, armature 50 of the distant relay G in its neutral position,conductors 118, 58, 57,56, 37 and 36 to the negative terminal 12 of thetransformer 11.

In this way, the armature 62 is held in its raised position, after ithas once been raised. by operating the re-set key 63, until thetrainenters the block B and causes the deenergization of the track relay Tand the breaking of the circuit number fourteen for the stick relay 60.From the foregoing it can be seen that an. engineer or motor man may keyby a stop signal; but the special arrangement of circuits shown is suchthat the entire control of the train is not restored to the engineer;but, on the contrary, the train is placed under the control of the speedcontrol apparatus which operates to bring it to a stop at the end of theblock into which the engineer has just keyed.

The system embodying this invention has been shown as designed to beoperated by alternating current, thereby deriving the advantage ofhaving the system unaffected by stray direct current; but it is to beunderstood that simple changes, obvious to those skilled in the art ofrallwaye signaling, can be made whereby direct current may be used asthe operating medium for this system. Various other changes in theparticular arrangement of the controlling circuits. may be made withoutdeparting from this invention, and the system shown may be combined withthe features of other systems; and I do not wish to be restricted to thedetails of the circuits shownand de scribed.

Although I have particularly described the construction of one physicalembodiment of my invention, and explained the operation and principlethereof, nevertheless, I desire to have it understood that the formselected is merely illustrative, but does not exhaust the possiblephysical embodiments of the idea of means underlying my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. In a system for controlling railway traflic, in combination: aplurality of electrically isolated track circuited blocks each having atrack relay; an insulated ramp at the entrance to each of said blocks, asource of electrical energy for establishing a (11 1 ference ofpotential between each of said ramps and the track rails; means governedby the track relay of the block next in advance of the blockcorresponding to a ramp for interrupting the connection between thecorresponding source and that ramp; and manually operable means forestablishing a connection between said ramp and sald sourceindependently of said means and for maintaining such connection until apasstraffic, in combination: a plurality means for controlling theaspects of said signal and for making and breaking the connectionbetween said sources and said ramp, said means being governed by thetrack relays of one or more of the blocks succeeding said signal andramp and causing different controlling conditions of said ramp anddifferent aspects of said signal depending on the number of unoccupiedblocks in advance thereof.

3. In a system for controlling railway of electrically isolated trackcircuited blocks, each having a track relay; an insulated ramp at theentrance of each of said blocks; a source of electrical energy forcreating a difference of potential between each of said ramps and thetrack rails; and means for controlling the connection between saidsource and said ramp governed by the track relays associated with thenext two blocks in advance of the corresponding block.

L'In a system for controlling railway traffic, in combination: aplurality of track circuited blocks, a signal at the entrance to eachblock; a polarized relay for selectively controlling the caution andclear. aspects of said signal; an energizing circuit'for said relay;means controlled by ,the track circuit of the next block in advance ofthe corresponding block. for controlling the continuity of said circuit,and means controlled trolling the by a track circuited blocks;

circuit on the second block in advance of the corresponding block fordetermining the polarity of said circuit.

5L In a system for controlling railway traflic, in combination: aplurality of track a signal at the entrance to each block; a polarizedthree position relay for selectively controlling the stop aspect andproceed aspects of said signal, a circuit forcontrolling said relay;means controlled by the track circuit of the corresponding block fordetermining the polarity of said circuit, and means controlled by thetrack circuit of the next block in advance for concontinuity of saidcircuit.

6. In a system for controlling railway traflic, in cbmbination: aplurality of track circuited blocks; an impulse device associated witheach block and adapted upon the entrance of a train into thecorresponding block to have its controlling condition changed from asafety condition'to either of two distinctive train controllingconditions; and circuits and controlling apparatus for governing thecontrolling conditions of each impulse device, said circuits andapparatusacting when'a train is present on any one of said blocks toplace the impulse device of the next block in the rear in one of itsdistinctive. train controlling conditions and theimpulse device of thesecond block in the rear in its other distinctive train controllingcondition.

.7. In a system circuited blocks for controlling railway traffic, incombination: a plurality of blocks each provided with a normally closedtrack circuit and a track relay; an impulse device associated with eachblock and encountered by a passing train prior to its entrance into thatblock; a high voltage source of current associated with each block; acircuit for energizing each impulse device including the correspondinghigh voltage source and controlled by the front contact of the trackrelay of the corresponding block; a lower voltage source of currentassociated with each block; a second circuit for energizing each impulsedevice, including the corresponding lower voltage source and controlledby the back contact of the track relay of the corresponding block; arelay for controlling said second circuit; and an energizing circuit forsaid relay controlled by the track relay of the next block in advance.

8. In a system for controlling railway traflic, in combination: aplurality of track circuited blocks each having a track relay; animpulse device located adjacent to the entrance end of each block;partial circuits for determining the controlling condition of eachimpulse device and each including a back contact of the track relay ofthe corresponding block; a relay for selectively controlling saidpartial circuits; and a circuit for energizing said relay including afront contact of the track relay of the next block in advance of thecorresponding block.

9. In a system for controlling railway traflic, in combination: aplurality of track x vehicle; circuits associated with each impulsetranmitting means for determining the nature of the controlling impulsestransmitted thereby; a polarized three- 0 sition relay for controllingeach of said circuits; a. circuit for controlling said relay; and meansgoverned by the track circuits of the blocks for rendering thecontinuity of said circuit dependent on the presence or; absence of atrain in the next block in advance of the corresponding block 1 5 andits polarity on the presence or absence of a train in the second blpckin advance of the corresponding block.

10. In a system for controlling railway traflic, in combination: aplurality of track a ramp located adjacent to the entrance end of eachblock; sources of current of different potential associated with eachramp; partial circuits associated with eachmamp and each including oneof said sources; and relays and controlling circuits governed by'saidtrack circuits for opening and closing said partial circuitsselectively, said 'relays and controlling circuits causing thepotentials applied to a ing said source for placing each impulse devicein condition to permit a train to pass without being stopped; a relaycontrolled by the track relay of the block next in advance of the blockcorresponding to each impulse device for controlling the correspondingcircuit; and manually controlled means having its initial operationdependcut on said relay being deenergized for establishing an auxiliarycircuit for said impulse device including said source, said means alsoacting to maintain said auxiliary circuit established until the trackrelay of the block corresponding to the associated impulse device isenergized.

12. In a system for controlling railway trafiic, in combination: arailroad track; impulse devices located at intervals along the track;trackway circuits and apparatus for rendering the controlling conditionof each impulse device dependent upon the extent of unoccupied track inadvance thereof; each impulse device when a train is within apredetermined distance'in advance thereof being caused to assume astopping condition; and manually controlled means associated with eachimpulse device and capable of being operated whenthe correspondingimpulse device is in its stopping condition for governing said circuitsand apparatus to change the controlling condition of the correspondingimpulse device from its stopping condition to another proceedcontrolling condition, said means aftereach manual operation beingautomatically maintained in its operatedcondition until a passing trainhas advanced a certain distance.

18. In a system for controlling railway traific, in combination: arailroad track divided into blocks; a trafiic controlled impulse deviceassociated with each block; an auxiliary circuit for energizing eachimpulse device; a manually operable circuit controller along the trackfor establishing said auxiliary circuit; an electromagnetic deviceadapted when energized to maintain said circuit controller closed; saidcircuit controller automatically opening when released unless maintainedclosed by said device; and a circuit governing said device andcontrolled by the track relay of the corresponding block.

l l. In a system for controlling railway trafic, in combination: arailroad track divided into blocks; a traffic controlled impulse deviceassociated with each block;'a source of current and a circuit forenergizing each impulse device; a relay for controlling said circuit; amanually operable circuit controller along the track; an energizingcircuit for said relay including said circuit controller; and a stickcircuit for said relay including a back contact of the track relay ofthe corresponding block.

15. In a system for controlling railway traffic, in combination: arailroad track divided into blocks; a'traflic controlled impulse deviceassociated with each block; an

auxiliary circuit for energizing each impulse .device; a relay forcontrolling said cuit controller along the track; an energizing circuitfor said relay including said circuit controller; and a stick circuitfor maintaining said relay energized after it has been initiallyenergized until the-passing train has advanced a certain distance.

WINTHROP K. HOWE.

auxiliary circuit; a manually operable cir-

